Results of adjuvant radiation therapy for locoregional perihilar cholangiocarcinoma after curative intent resection

PURPOSE: This study sought to define the role of adjuvant radiation therapy (RT) for patients with curative intent resection of perihilar cholangiocarcinoma (pCCA). PATIENTS AND METHODS: By using the Surveillance, Epidemiology and End Results (SEER) registry, 1,917 patients with non-metastatic pCCA who underwent surgical resection from 1988 to 2009 were included in this study. Propensity score methods were used to compare the survival outcomes of patients treated with and without adjuvant RT after controlling for selection bias. RESULTS: Of the 1,917 patients, 762 (39.7%) received adjuvant RT. In the unmatched population, median overall survival (OS) for patients receiving adjuvant RT compared with those undergoing surgery alone was 23 versus 22 months (P=0.651). Patients who received adjuvant RT were younger (65 vs 68 years, P<0.001), had more regional diseases (86.0% vs 76.7%, P<0.001), and had more positive lymph nodes (43.8% vs 32.2%, P<0.001). In the matched population, adjuvant RT did not show better OS (22 vs 23 months, P=0.978) or cancer-specific survival (CSS) (17 vs 18 months, P=0.554). CONCLUSION: Adjuvant RT is not associated with improved survival of patients with resected pCCA. These data suggest that adjuvant RT should not be routinely used to treat patients with pCCA outside research trials. Ideally, prospective randomized trials should be performed to verify the conclusion of this study.